I've build a custom linux kernel from the vanilla source tree using the deb-pkg target:

make deb-pkg

After that package has been built I've got several .deb files. However I'd like to upload those files to a private repository which is managed by reprepro. I need a .changes file for that. I could generated the changes file with

dpkg-genchanges

This in turn needs a .dsc file which I don't have.

How do I generated a .dsc (and .changes) file from a vanilla linux source tree from which I've build .deb packages using make deb-pkg?